For me, it really helps to have a nice warm liner glove, thin enough to allow me to do camp chores without taking off the gloves but that will keep my hands from getting chilled. For Christmas I was given a pair of Smartwool liner gloves which are wonderful for this purpose (they also don't melt when I grab a hot pot). If I don't need dexterity at the moment, I immediately put mittens on over them. If it's really cold (well below freezing), it's liner gloves plus fleece mittens plus waterproof shells. I find this triple combo too warm for active hiking (my hands sweat), but I certainly use it in camp or at rest stops.

MNS's idea of using the chemical warmers on your wrists also sounds good. I certainly hope you can work something out!